CA2046567C - Method of producing an air electrode material for solid electrolyte type fuel cells - Google Patents
Method of producing an air electrode material for solid electrolyte type fuel cellsInfo
- Publication number
- CA2046567C CA2046567C CA002046567A CA2046567A CA2046567C CA 2046567 C CA2046567 C CA 2046567C CA 002046567 A CA002046567 A CA 002046567A CA 2046567 A CA2046567 A CA 2046567A CA 2046567 C CA2046567 C CA 2046567C
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- Prior art keywords
- air electrode
- solid electrolyte
- xaxmno3
- electrode material
- synthesized product
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- 239000007784 solid electrolyte Substances 0.000 title claims abstract description 47
- 238000000034 method Methods 0.000 title claims abstract description 36
- 239000007772 electrode material Substances 0.000 title claims abstract description 35
- 239000000446 fuel Substances 0.000 title claims abstract description 20
- 239000000047 product Substances 0.000 claims abstract description 35
- 238000010304 firing Methods 0.000 claims abstract description 16
- 229910052751 metal Inorganic materials 0.000 claims abstract description 14
- 239000002184 metal Substances 0.000 claims abstract description 14
- 239000007795 chemical reaction product Substances 0.000 claims abstract description 10
- 150000001875 compounds Chemical class 0.000 claims abstract description 7
- 239000011572 manganese Substances 0.000 claims abstract description 7
- 238000002156 mixing Methods 0.000 claims abstract description 6
- 229910052684 Cerium Inorganic materials 0.000 claims abstract description 5
- 229910052769 Ytterbium Inorganic materials 0.000 claims abstract description 5
- 229910052788 barium Inorganic materials 0.000 claims abstract description 5
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 5
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 5
- 229910052727 yttrium Inorganic materials 0.000 claims abstract description 5
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 5
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims abstract description 4
- 229910052746 lanthanum Inorganic materials 0.000 claims abstract description 4
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims abstract description 4
- 150000002604 lanthanum compounds Chemical class 0.000 claims abstract description 4
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 4
- 150000002697 manganese compounds Chemical class 0.000 claims abstract description 4
- 239000011369 resultant mixture Substances 0.000 claims abstract description 4
- 229910052712 strontium Inorganic materials 0.000 claims abstract description 4
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 32
- 239000011248 coating agent Substances 0.000 claims description 21
- 238000000576 coating method Methods 0.000 claims description 21
- 239000000843 powder Substances 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 10
- 239000002002 slurry Substances 0.000 claims description 8
- 239000011230 binding agent Substances 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum oxide Inorganic materials [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 claims description 3
- 238000002360 preparation method Methods 0.000 claims description 3
- 239000007921 spray Substances 0.000 claims description 3
- 229910002076 stabilized zirconia Inorganic materials 0.000 claims description 3
- 239000003795 chemical substances by application Substances 0.000 claims description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L manganese oxide Inorganic materials [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 claims description 2
- 239000004615 ingredient Substances 0.000 claims 2
- 238000010298 pulverizing process Methods 0.000 claims 2
- 239000002131 composite material Substances 0.000 claims 1
- 230000015572 biosynthetic process Effects 0.000 abstract description 6
- 229910002230 La2Zr2O7 Inorganic materials 0.000 abstract description 3
- 239000000463 material Substances 0.000 description 7
- 239000008188 pellet Substances 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- KTUFCUMIWABKDW-UHFFFAOYSA-N oxo(oxolanthaniooxy)lanthanum Chemical compound O=[La]O[La]=O KTUFCUMIWABKDW-UHFFFAOYSA-N 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 230000002194 synthesizing effect Effects 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- RZVAJINKPMORJF-UHFFFAOYSA-N Acetaminophen Chemical group CC(=O)NC1=CC=C(O)C=C1 RZVAJINKPMORJF-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 235000008075 Pistacia terebinthus Nutrition 0.000 description 1
- 240000006705 Pistacia terebinthus Species 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 235000010216 calcium carbonate Nutrition 0.000 description 1
- ZMIGMASIKSOYAM-UHFFFAOYSA-N cerium Chemical compound [Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce] ZMIGMASIKSOYAM-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003034 coal gas Substances 0.000 description 1
- 238000000748 compression moulding Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 238000003411 electrode reaction Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- GEYXPJBPASPPLI-UHFFFAOYSA-N manganese(III) oxide Inorganic materials O=[Mn]O[Mn]=O GEYXPJBPASPPLI-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000009718 spray deposition Methods 0.000 description 1
- LEDMRZGFZIAGGB-UHFFFAOYSA-L strontium carbonate Chemical compound [Sr+2].[O-]C([O-])=O LEDMRZGFZIAGGB-UHFFFAOYSA-L 0.000 description 1
- 229910000018 strontium carbonate Inorganic materials 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- NAWDYIZEMPQZHO-UHFFFAOYSA-N ytterbium Chemical compound [Yb] NAWDYIZEMPQZHO-UHFFFAOYSA-N 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G45/00—Compounds of manganese
- C01G45/12—Complex oxides containing manganese and at least one other metal element
- C01G45/1221—Manganates or manganites with trivalent manganese, tetravalent manganese or mixtures thereof
- C01G45/125—Manganates or manganites with trivalent manganese, tetravalent manganese or mixtures thereof of the type (MnO3)n-, e.g. CaMnO3
- C01G45/1264—Manganates or manganites with trivalent manganese, tetravalent manganese or mixtures thereof of the type (MnO3)n-, e.g. CaMnO3 containing rare earths, e.g. (La1-xCax)MnO3 or LaMnO3
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/016—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on manganites
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/90—Selection of catalytic material
- H01M4/9016—Oxides, hydroxides or oxygenated metallic salts
- H01M4/9025—Oxides specially used in fuel cell operating at high temperature, e.g. SOFC
- H01M4/9033—Complex oxides, optionally doped, of the type M1MeO3, M1 being an alkaline earth metal or a rare earth, Me being a metal, e.g. perovskites
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Ceramic Engineering (AREA)
- Electrochemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Structural Engineering (AREA)
- Inert Electrodes (AREA)
- Fuel Cell (AREA)
Abstract
An excellent method of producing an air electrode material for solid electrolyte type fuel cells is provided which can prevent cracks and peeling-off of the air electrode caused by a difference of thermal shrinkages of the air electrode and the solid electrolyte as well as formation of highly electric resistant reaction products, such as La2Zr2O7, etc., at the time of providing the fuel electrode or the solid electrolyte, and which can prevent deformation and shrinkage of the air electrode material even when it is used as the self-supporting type air electrode material at high temperatures. The method comprises a process of mixing lanthanum or a lanthanum compound, manganese or a manganese compound, and a metal A or a compound of the metal A wherein A is at least one metal selected from the group consisting of Sr, Ca, Mg, Y, Ce, Yb, Zn and Ba, a process of firing the resultant mixture at a temperature of at least 1,400°C to obtain a synthesized product La1-xAxMnO3 wherein x is 0<x?0.5 and A is as described above, and a process of treating the synthesized product La1-xAxMnO3 to produce an air electrode material substantially consisting of La1-xAxMnO3.
Description
2~46567 METHOD OF PRODUCING AN AIR ELECTRODE MATERIAL
FOR SOLID ELECTROLYTE TYPE FUEL CELLS
The present invention relates to a method of producing an air electrode material for solid electrolyte type fuel cells.
Recently, solid electrolyte type fuel cells 05 (usually called "SOFC") have attracted attentions as exceedingly promising electric generators having advantages of a high generation efficiency, low public nuisances, and diversity of fuels (naphtha, natural gas, methanol, reformed coal gas, etc.).
A current important task in developing SOFC is how to lower an overvoltage of the air electrode.
Currently, voltage drop of SOFC is largely caused by an overvoltage of the air electrode.
Disturbance of electrode reaction and resistance due to an insulation layer formed on an intersurface between the air electrode and the stabilized zirconia solid electrolyte, are pointed out as the causes of the overvoltage.
Syntheses of a material Lao.6Cao.4MnO3 were reported, for example, in Mizusaki et al "Electrode Thickness, Microstructure and Electrode Properties of Lao.6Cao.4Mo3 (M=Mn,Co)/YSZ System Air Electrode for High Temperature Solid Oxide Fuel Cells" described on Bulletin of the Chemical Society of Japan, [9], pp 1623-1629, 1988, wherein La2O3, CaCO3 and Mn2O3 powders are mixed in a ball mill with ethanol for 24 hours, once pulverized and sieved, again fired at 1,200C, and pulverized. The thus obtained synthetic Lao.6Cao.4MO3 powder is again pulverized in a mortar, mixed with terebinth oil to form a paste, applied on a surface of a solid electrolyte YSZ pellet, and baked at 1,100C for 4 hours to prepare the material Lao.6Cao.4MnO3 of the air electrode. However, the method has a drawback in that cracks are formed in the air electrode due to a difference of thermal shrinkages between the solid electrolyte pellet and the air electrode if the application amount of the paste exceeds 50 mg/cm2.
1~ Also, reaction products are formed at the intersurface between the solid electrolyte pellet and the material Lao.6Cao.4MnO3 at the time of baking the fuel electrode onto the other surface of the solid electrolyte pellet at a high temperature of, e.g., 1,300C.
On the other hand, instead of providing the coating of the air electrode on the surface of the porous support and sequentially arranging the solid electrolyte and the fuel electrode on the coating, a technique was proposed of using the porous air electrode perse as the structural support. By this technique the whole structure of SOFC can be simplified as well as the production process, and the production 20~6567 cost can be reduced.
However, even in that technique, cracks are liable to form in the solid electrolyte or the air electrode at the time of coating the solid electrolyte on the surface of the porous air electrode at a high temperature of e.g. 1,400C, and the reaction products are formed at the interface between the solid electrolyte and the air electrode. Moreover, when the self-supporting type porous air electrode is used as the support, the porous air electrode is largely deformed and shrinked if it is exposed to such high temperature as mentioned above.
An object of the present invention is to prevent cracks and peeling-off caused by a difference of 1~ thermal shrinkages between the solid electrolyte and the air electrode and to prevent formation of the highly electric resistant reaction products, such as La2Zr2O7, etc., at the interface between the air electrode and the solid electrolyte, when forming the solid electrolyte and the fuel electrode.
Another object of the present invention is to provide a method of producing a material for the air electrode of a self-supporting type for solid electrolyte type fuel cells wherein deformation and shrinkage of the material for the air electrode can be prevented even when the material is exposed to a high temperature.
A further object of the present invention will become apparent from the ensuing descriptions.
The present invention is a method of producing an air electrode material for solid electrolyte type fuel cells, comprising a process of mixing lanthanum or a lanthanum compound, manganese or a manganese compound, and a metal A or a compound of the metal A wherein A is at least one ~ selected from the group consisting of Sr, Ca, Mg, Y, Ce, Yb, Zn and Ba, a process of firing the resultant mixture at a temperature of at least 1,400C to obtain a synthesized product Lal xAxMnO3 wherein x is O<x_0.5 and A is as described above, and a process of treating the synthesized product Lal_xAxMnO3 to produce an air electrode material 16 substantially consisting of Lal_xAxMnO3.
In the present invention, at first, La or a La compound, Mn or a Mn compound, and a metal M or a M
compound, are mixed, and the resultant mixture is prefired at a temperature of at least 1,400C to obtain a synthesized product Lal_xAxMnO3. The present invention has a significant characteristic feature of effecting the prefiring step of preparing the synthesized product at a higher temperature range than conventional art. By virtue of using the Lal_xAxMnO3 synthesized at a high temperature range, cracks and peeling-off resulting from a difference of thermal shrinkages between the air electrode material and the 2046~67 solid electrolyte can be prevented from occurring as well as the formation of high resistance substances at the interface between the air electrode and the solid electrolyte, even when the air electrode material is heated to a high of, e.g., 1,300C. Also, if the electrode material is used to prepare a self-supporting type air electrode tube, bending deformation and shrinkage of the self-supporting type air electrode tube can be suppressed, even when the air electrode tube is exposed to a high temperature of, e.g., 1,300C. This is considered due to a reason that the synthesized product obtained by the prefiring at a high temperature range of at least 1,400C has a low sintering property and hence the grains or particles of the synthesized 16 product have a low activity at high temperatures.
Firing temperature of 1,500-1,700C at the time of synthesizing the synthesized product is more preferable.
Before synthesizing the synthesized product by prefiring, a kneaded mixture of the raw materials powders is preferably subjected to press molding, extrusion forming, vacuum extrusion or the like compression molding to make the bulk density of the mixture to at least 40% of the intrinsic density, in order to further increase gas permeability and mechanical strength of the final product, particularly the finally fired product, namely, the air electrode material.
Next, the process of treating the synthesized product Lal_xAxMnO3 to prepare the air electrode material will be explained.
In case when the self-supporting type air electrode body (tubular shape, plate shape, etc.), the synthesized product is at first pulverized preferably to an average grain size of 1-10 ~m. If the pulverized powder has an average grain size of less than 1 ~m, the resultant air electrode body becomes so dense that a desired porosity of at least 20% can hardly be obtained. If the pulverized powder has an average grain size exceeding 10 ~m, the mechanical strength of the air electrode body becomes insufficient.
1~ Namely, the thus obtained powder is added with water and an organic binder, formed into a desired shape, and subjected to a final firing to prepare the air electrode body of a desired shape. A coating of a solid electrolyte zirconia is provided on a surface of the air electrode body at a high temperature of, e.g., 1,400C and a coating of a fuel electrode is provided.
Alternatively, the coating of the synthesized product may be formed on the surface of the porous support zirconia to prepare the coating type air electrode material. Further alternatively, the solid electrolyte zirconia and the fuel electrode are superposed to preliminarily form an integrated body, and the coating of the above synthesized product may be provided on the surface of the solid electrolyte zirconia to prepare the coating type air electrode.
In these cases, there are a few methods of forming the coating of the synthesized product.
For example, similarly as in the case of preparing the above described self-supporting type air electrode body, the synthesized product is pulverized preferably to a fineness of an average grain size of 1-10 ~m, the resultant powder is added with water, a binder and a pore-increasing agent to prepare a slurry, the thus obtained slurry is applied on the surface of the porous support zirconia or the solid electrolyte zirconia, and then subjected to the final firing to obtain the coating 1~ type air electrode. In an alternative method, the coating of the synthesized product is provided on a surface of the porous support zirconia or the solid electrolyte zirconia by thermal melt spray or vapor deposition, etc.
In the abovementioned methods, in case when finally firing the kneaded mixture or the slurry to prepare the air electrode material, the firing temperature is preferably 1,300-1,800C, more preferably 1,500-1,800C. If the firing temperature is less than 1,300C, sintering of the kneaded mixture or the slurry is incomplete to decrease the strength of the air electrode material. If the firing temperature exceeds 1,800C, the air electrode material becomes too dense to obtain a desired air-penetration property.
In the synthesized product Lal_xAxMnO3, x is defined as x-0.5, in order to make the thermal expansion coefficient of the air electrode material approach to that of the solid electrode zirconia as far as possible.
Hereinafter, the present invention will be explained in more detail with reference to examples.
Example 1 Preparation of the air electrode material La2O3, Mn3O4 and SrCO3 of desired amounts are mixed in a wet type mixer, dried, disintegrated, added with a binder, and extruded to a columnar green body of 1~ a diameter of 60 mm and a height of 200 mm. Bulk density is 50% of intrinsic density.
The green body is prefired at a temperature of 1,100C, 1,200C, 1,300C, 1,400C, 1,500C or 1,600C
to synthesize synthesized products Lao.OSro.2Mno3~ and the synthesized products are respectively pulverized in a ball mill to a fineness of an average grain size of 4-6 ~m.
The thus obtained powders are added with an organic binder and water, press formed into bodies of a shape of a length of 200 mm, a width of 100 mm and a height of 10 mm, and fired to obtain fired bodies of porosities of around 25% and 35%. In this case, the 2046~67 final firing temperature is so adjusted that the finally obtained air electrode materials have a porosity of 25%
or 35%.
Then, a sample of a columnar shape of 06 a diameter of 20 mm and a height of 2 mm is cut out from each of the above fired bodies, and applied with a coating of a 8 mole solid electrolyte zirconia to a thickness of 100 ~m by plasma spray. Then, the laminated disc shaped samples are heat treated at 1,300C (which is a temperature of the later described forming of the fuel electrode), and left to cool.
The cooled samples are checked on presence or non-presence of cracks of the air electrode or the solid electrolyte coating caused by a difference of thermal 16 shrinkages of the air electrode and the solid electrolyte coating. The results are shown in the following Table 1.
Table 1 temperature (C) 1100 1200 1300 1400 lS00 1600 Final firing 1420 1380 1455 1420 1495 1455 1540 1500 1590 1545 1640 1590 temperature (C) Porosity (~) 25.1 34.9 25.2 35.0 25.2 35.1 25.1 34.8 24.8 35.2 25.0 35.3 Cracks X X X X O X O O O O O O
Note: the symbol O means non-presence, the symbol X means presence As seen from the results in the above Table 1, cracks are not formed on the solid electrolyte film, when the prefiring temperature of the synthesized product is at least 1,400C.
Example 2 In the same manner as described in Example 1, fired bodies of a porosity of around 25% or 35~ are obtained.
Then, a sample of a columnar shape of a length of 20 mm, a width of 20 mm and a thickness of 2 mm is cut out from each of the above air electrode materials, and coated at a surface with a slurry of 8 mole Y2O3 stabilized zirconia by brushing.
Thereafter, the coated samples are fired at 1~ 1,300C for 5 hours, and left to cool. The cooled samples are checked on formation of the reaction product La2Zr2O7 at the interface between the air electrode and the solid electrolyte film. The results are shown in the following Table 2.
Table 2 temperature (C) 1100 1200 1300 1400 1500 1600 Porosity (%) 25.1 34.9 25.2 35.0 25.2 35.1 25.1 34.8 24.8 35.2 25.0 35.3 Reaction product X X X X X X O O O O O O
Note: the symbol X means presence of the reaction product, and the symbol O
means non-presence of the reaction product As seen from the results in the above Table 2, the reaction product or the reaction at the interface between the air electrode material and the solid electrolyte zirconia of the finally obtained product can 06 be obviated, when the prefiring temperature at the time of synthesis is at least 1,400C.
Example 3 In the same manner as described in Example 1, fired bodies of a porosity of around 25% or 35% are obtained.
Then, a strip-shaped sample of a height of 3 mm, a width of 2 mm and a length of 200 mm is cut out from each of the above air electrode materials. Then, the strip-shaped samples are supported by each two 1~ supporting points. The two supporting points are set to have a distance of 120 mm.
The samples are held in this state at 1,300C
for 5 hours. By this heat treatment, the central portions of the strip-shaped samples are bent downwardly by its own weight, so that the whole samples are deformed in shape to a recessed state. Therefore, the strip-shaped samples are measured on the displacement or deformation of the central portion from the original non-deformed position. The results are shown in the following Table 3.
Table 3 temperature (C) 1100 1200 1300 1400 1500 1600 Poro~ity (~) 25.1 34.9 25.2 35,0 25.2 35.1 25.1 34.B 24.8 35.2 25.0 35.3 Deformation (mm) 57.4 66.1 42.6 51.6 29.5 35.6 13.7 19.8 1.6 11.0 0.1 0.2 2046~57 A permissible limit of the bent or deformation at the firing of the self-supporting type air electrode tube is 20 mm from a viewpoint of practical use, so that the deformations of the strip-shaped samples are within the permissible limit when the prefiring temperature is at least 1,400C.
Examples 4-6 The amount of addition of Sr in the synthesized product Lao.OSrO.2MnO3 of Examples 1-3 is changed to obtain synthesized products Lal_xSrxMnO3 (wherein x=0.1, 0.3, 0.4 or 0.5), and substantially the same results as in the cases of Examples 1-3 are obtained.
Also, instead of Sr as the doping agent metal A, calcium, magnesium, yttrium, cerium, ytterbium, zinc, 16 or barium is used in the green body for preparing the air electrode material, and substantially the similar results as described above are obtained.
According to the method of the present invention, a mixture of raw-materials of the air electrode material is prefired at a temperature of at least 1,400C to obtain the synthesized product Lal_xAxMnO3, so that the synthesized product has a low sintering property and the grains of the synthesized product have a low activity at high temperatures.
By using such synthesized product to prepare the air electrode material, cracks or peeling-off of the solid electrolyte due to a difference of thermal expansions of 20~6~67 the air electrode and the solid electrolyte can be prevented as well as the formation of the high resistance materials at the interface between the air electrode and the solid electrolyte, even when the air electrode material is heated to a high temperature of, e.g., 1,300C. Moreover, when the self-supporting type air electrode body is prepared using the air electrode material, bent or deformation and shrinkage of the air electrode can be suppressed, even if it exposed to high temperatures.
Although the present invention has been explained with reference to specific values and embodiments, it will of course be apparent to those skilled in the art that the present invention is not 16 limited thereto and many vibrations and modifications are possible without departing from the broad aspect and scope of the present invention as defined in the appended claims.
FOR SOLID ELECTROLYTE TYPE FUEL CELLS
The present invention relates to a method of producing an air electrode material for solid electrolyte type fuel cells.
Recently, solid electrolyte type fuel cells 05 (usually called "SOFC") have attracted attentions as exceedingly promising electric generators having advantages of a high generation efficiency, low public nuisances, and diversity of fuels (naphtha, natural gas, methanol, reformed coal gas, etc.).
A current important task in developing SOFC is how to lower an overvoltage of the air electrode.
Currently, voltage drop of SOFC is largely caused by an overvoltage of the air electrode.
Disturbance of electrode reaction and resistance due to an insulation layer formed on an intersurface between the air electrode and the stabilized zirconia solid electrolyte, are pointed out as the causes of the overvoltage.
Syntheses of a material Lao.6Cao.4MnO3 were reported, for example, in Mizusaki et al "Electrode Thickness, Microstructure and Electrode Properties of Lao.6Cao.4Mo3 (M=Mn,Co)/YSZ System Air Electrode for High Temperature Solid Oxide Fuel Cells" described on Bulletin of the Chemical Society of Japan, [9], pp 1623-1629, 1988, wherein La2O3, CaCO3 and Mn2O3 powders are mixed in a ball mill with ethanol for 24 hours, once pulverized and sieved, again fired at 1,200C, and pulverized. The thus obtained synthetic Lao.6Cao.4MO3 powder is again pulverized in a mortar, mixed with terebinth oil to form a paste, applied on a surface of a solid electrolyte YSZ pellet, and baked at 1,100C for 4 hours to prepare the material Lao.6Cao.4MnO3 of the air electrode. However, the method has a drawback in that cracks are formed in the air electrode due to a difference of thermal shrinkages between the solid electrolyte pellet and the air electrode if the application amount of the paste exceeds 50 mg/cm2.
1~ Also, reaction products are formed at the intersurface between the solid electrolyte pellet and the material Lao.6Cao.4MnO3 at the time of baking the fuel electrode onto the other surface of the solid electrolyte pellet at a high temperature of, e.g., 1,300C.
On the other hand, instead of providing the coating of the air electrode on the surface of the porous support and sequentially arranging the solid electrolyte and the fuel electrode on the coating, a technique was proposed of using the porous air electrode perse as the structural support. By this technique the whole structure of SOFC can be simplified as well as the production process, and the production 20~6567 cost can be reduced.
However, even in that technique, cracks are liable to form in the solid electrolyte or the air electrode at the time of coating the solid electrolyte on the surface of the porous air electrode at a high temperature of e.g. 1,400C, and the reaction products are formed at the interface between the solid electrolyte and the air electrode. Moreover, when the self-supporting type porous air electrode is used as the support, the porous air electrode is largely deformed and shrinked if it is exposed to such high temperature as mentioned above.
An object of the present invention is to prevent cracks and peeling-off caused by a difference of 1~ thermal shrinkages between the solid electrolyte and the air electrode and to prevent formation of the highly electric resistant reaction products, such as La2Zr2O7, etc., at the interface between the air electrode and the solid electrolyte, when forming the solid electrolyte and the fuel electrode.
Another object of the present invention is to provide a method of producing a material for the air electrode of a self-supporting type for solid electrolyte type fuel cells wherein deformation and shrinkage of the material for the air electrode can be prevented even when the material is exposed to a high temperature.
A further object of the present invention will become apparent from the ensuing descriptions.
The present invention is a method of producing an air electrode material for solid electrolyte type fuel cells, comprising a process of mixing lanthanum or a lanthanum compound, manganese or a manganese compound, and a metal A or a compound of the metal A wherein A is at least one ~ selected from the group consisting of Sr, Ca, Mg, Y, Ce, Yb, Zn and Ba, a process of firing the resultant mixture at a temperature of at least 1,400C to obtain a synthesized product Lal xAxMnO3 wherein x is O<x_0.5 and A is as described above, and a process of treating the synthesized product Lal_xAxMnO3 to produce an air electrode material 16 substantially consisting of Lal_xAxMnO3.
In the present invention, at first, La or a La compound, Mn or a Mn compound, and a metal M or a M
compound, are mixed, and the resultant mixture is prefired at a temperature of at least 1,400C to obtain a synthesized product Lal_xAxMnO3. The present invention has a significant characteristic feature of effecting the prefiring step of preparing the synthesized product at a higher temperature range than conventional art. By virtue of using the Lal_xAxMnO3 synthesized at a high temperature range, cracks and peeling-off resulting from a difference of thermal shrinkages between the air electrode material and the 2046~67 solid electrolyte can be prevented from occurring as well as the formation of high resistance substances at the interface between the air electrode and the solid electrolyte, even when the air electrode material is heated to a high of, e.g., 1,300C. Also, if the electrode material is used to prepare a self-supporting type air electrode tube, bending deformation and shrinkage of the self-supporting type air electrode tube can be suppressed, even when the air electrode tube is exposed to a high temperature of, e.g., 1,300C. This is considered due to a reason that the synthesized product obtained by the prefiring at a high temperature range of at least 1,400C has a low sintering property and hence the grains or particles of the synthesized 16 product have a low activity at high temperatures.
Firing temperature of 1,500-1,700C at the time of synthesizing the synthesized product is more preferable.
Before synthesizing the synthesized product by prefiring, a kneaded mixture of the raw materials powders is preferably subjected to press molding, extrusion forming, vacuum extrusion or the like compression molding to make the bulk density of the mixture to at least 40% of the intrinsic density, in order to further increase gas permeability and mechanical strength of the final product, particularly the finally fired product, namely, the air electrode material.
Next, the process of treating the synthesized product Lal_xAxMnO3 to prepare the air electrode material will be explained.
In case when the self-supporting type air electrode body (tubular shape, plate shape, etc.), the synthesized product is at first pulverized preferably to an average grain size of 1-10 ~m. If the pulverized powder has an average grain size of less than 1 ~m, the resultant air electrode body becomes so dense that a desired porosity of at least 20% can hardly be obtained. If the pulverized powder has an average grain size exceeding 10 ~m, the mechanical strength of the air electrode body becomes insufficient.
1~ Namely, the thus obtained powder is added with water and an organic binder, formed into a desired shape, and subjected to a final firing to prepare the air electrode body of a desired shape. A coating of a solid electrolyte zirconia is provided on a surface of the air electrode body at a high temperature of, e.g., 1,400C and a coating of a fuel electrode is provided.
Alternatively, the coating of the synthesized product may be formed on the surface of the porous support zirconia to prepare the coating type air electrode material. Further alternatively, the solid electrolyte zirconia and the fuel electrode are superposed to preliminarily form an integrated body, and the coating of the above synthesized product may be provided on the surface of the solid electrolyte zirconia to prepare the coating type air electrode.
In these cases, there are a few methods of forming the coating of the synthesized product.
For example, similarly as in the case of preparing the above described self-supporting type air electrode body, the synthesized product is pulverized preferably to a fineness of an average grain size of 1-10 ~m, the resultant powder is added with water, a binder and a pore-increasing agent to prepare a slurry, the thus obtained slurry is applied on the surface of the porous support zirconia or the solid electrolyte zirconia, and then subjected to the final firing to obtain the coating 1~ type air electrode. In an alternative method, the coating of the synthesized product is provided on a surface of the porous support zirconia or the solid electrolyte zirconia by thermal melt spray or vapor deposition, etc.
In the abovementioned methods, in case when finally firing the kneaded mixture or the slurry to prepare the air electrode material, the firing temperature is preferably 1,300-1,800C, more preferably 1,500-1,800C. If the firing temperature is less than 1,300C, sintering of the kneaded mixture or the slurry is incomplete to decrease the strength of the air electrode material. If the firing temperature exceeds 1,800C, the air electrode material becomes too dense to obtain a desired air-penetration property.
In the synthesized product Lal_xAxMnO3, x is defined as x-0.5, in order to make the thermal expansion coefficient of the air electrode material approach to that of the solid electrode zirconia as far as possible.
Hereinafter, the present invention will be explained in more detail with reference to examples.
Example 1 Preparation of the air electrode material La2O3, Mn3O4 and SrCO3 of desired amounts are mixed in a wet type mixer, dried, disintegrated, added with a binder, and extruded to a columnar green body of 1~ a diameter of 60 mm and a height of 200 mm. Bulk density is 50% of intrinsic density.
The green body is prefired at a temperature of 1,100C, 1,200C, 1,300C, 1,400C, 1,500C or 1,600C
to synthesize synthesized products Lao.OSro.2Mno3~ and the synthesized products are respectively pulverized in a ball mill to a fineness of an average grain size of 4-6 ~m.
The thus obtained powders are added with an organic binder and water, press formed into bodies of a shape of a length of 200 mm, a width of 100 mm and a height of 10 mm, and fired to obtain fired bodies of porosities of around 25% and 35%. In this case, the 2046~67 final firing temperature is so adjusted that the finally obtained air electrode materials have a porosity of 25%
or 35%.
Then, a sample of a columnar shape of 06 a diameter of 20 mm and a height of 2 mm is cut out from each of the above fired bodies, and applied with a coating of a 8 mole solid electrolyte zirconia to a thickness of 100 ~m by plasma spray. Then, the laminated disc shaped samples are heat treated at 1,300C (which is a temperature of the later described forming of the fuel electrode), and left to cool.
The cooled samples are checked on presence or non-presence of cracks of the air electrode or the solid electrolyte coating caused by a difference of thermal 16 shrinkages of the air electrode and the solid electrolyte coating. The results are shown in the following Table 1.
Table 1 temperature (C) 1100 1200 1300 1400 lS00 1600 Final firing 1420 1380 1455 1420 1495 1455 1540 1500 1590 1545 1640 1590 temperature (C) Porosity (~) 25.1 34.9 25.2 35.0 25.2 35.1 25.1 34.8 24.8 35.2 25.0 35.3 Cracks X X X X O X O O O O O O
Note: the symbol O means non-presence, the symbol X means presence As seen from the results in the above Table 1, cracks are not formed on the solid electrolyte film, when the prefiring temperature of the synthesized product is at least 1,400C.
Example 2 In the same manner as described in Example 1, fired bodies of a porosity of around 25% or 35~ are obtained.
Then, a sample of a columnar shape of a length of 20 mm, a width of 20 mm and a thickness of 2 mm is cut out from each of the above air electrode materials, and coated at a surface with a slurry of 8 mole Y2O3 stabilized zirconia by brushing.
Thereafter, the coated samples are fired at 1~ 1,300C for 5 hours, and left to cool. The cooled samples are checked on formation of the reaction product La2Zr2O7 at the interface between the air electrode and the solid electrolyte film. The results are shown in the following Table 2.
Table 2 temperature (C) 1100 1200 1300 1400 1500 1600 Porosity (%) 25.1 34.9 25.2 35.0 25.2 35.1 25.1 34.8 24.8 35.2 25.0 35.3 Reaction product X X X X X X O O O O O O
Note: the symbol X means presence of the reaction product, and the symbol O
means non-presence of the reaction product As seen from the results in the above Table 2, the reaction product or the reaction at the interface between the air electrode material and the solid electrolyte zirconia of the finally obtained product can 06 be obviated, when the prefiring temperature at the time of synthesis is at least 1,400C.
Example 3 In the same manner as described in Example 1, fired bodies of a porosity of around 25% or 35% are obtained.
Then, a strip-shaped sample of a height of 3 mm, a width of 2 mm and a length of 200 mm is cut out from each of the above air electrode materials. Then, the strip-shaped samples are supported by each two 1~ supporting points. The two supporting points are set to have a distance of 120 mm.
The samples are held in this state at 1,300C
for 5 hours. By this heat treatment, the central portions of the strip-shaped samples are bent downwardly by its own weight, so that the whole samples are deformed in shape to a recessed state. Therefore, the strip-shaped samples are measured on the displacement or deformation of the central portion from the original non-deformed position. The results are shown in the following Table 3.
Table 3 temperature (C) 1100 1200 1300 1400 1500 1600 Poro~ity (~) 25.1 34.9 25.2 35,0 25.2 35.1 25.1 34.B 24.8 35.2 25.0 35.3 Deformation (mm) 57.4 66.1 42.6 51.6 29.5 35.6 13.7 19.8 1.6 11.0 0.1 0.2 2046~57 A permissible limit of the bent or deformation at the firing of the self-supporting type air electrode tube is 20 mm from a viewpoint of practical use, so that the deformations of the strip-shaped samples are within the permissible limit when the prefiring temperature is at least 1,400C.
Examples 4-6 The amount of addition of Sr in the synthesized product Lao.OSrO.2MnO3 of Examples 1-3 is changed to obtain synthesized products Lal_xSrxMnO3 (wherein x=0.1, 0.3, 0.4 or 0.5), and substantially the same results as in the cases of Examples 1-3 are obtained.
Also, instead of Sr as the doping agent metal A, calcium, magnesium, yttrium, cerium, ytterbium, zinc, 16 or barium is used in the green body for preparing the air electrode material, and substantially the similar results as described above are obtained.
According to the method of the present invention, a mixture of raw-materials of the air electrode material is prefired at a temperature of at least 1,400C to obtain the synthesized product Lal_xAxMnO3, so that the synthesized product has a low sintering property and the grains of the synthesized product have a low activity at high temperatures.
By using such synthesized product to prepare the air electrode material, cracks or peeling-off of the solid electrolyte due to a difference of thermal expansions of 20~6~67 the air electrode and the solid electrolyte can be prevented as well as the formation of the high resistance materials at the interface between the air electrode and the solid electrolyte, even when the air electrode material is heated to a high temperature of, e.g., 1,300C. Moreover, when the self-supporting type air electrode body is prepared using the air electrode material, bent or deformation and shrinkage of the air electrode can be suppressed, even if it exposed to high temperatures.
Although the present invention has been explained with reference to specific values and embodiments, it will of course be apparent to those skilled in the art that the present invention is not 16 limited thereto and many vibrations and modifications are possible without departing from the broad aspect and scope of the present invention as defined in the appended claims.
Claims (10)
1. A method of producing an air electrode material for solid electrolyte type fuel cells comprising a porous air electrode, a porous fuel electrode and a solid electrolyte between the air electrode and the fuel electrode, the said air electrode being substantially free of cracks and peeling-off caused by a difference of thermal shrinkages between the solid electrolyte and the air electrode and being substantially free of highly electric resistant reaction products at an interface between the air electrode and the solid electrolyte, which method comprises:
(i) mixing [a] lanthanum or a lanthanum compound, [b]
manganese or a manganese compound and [c] a metal A or a compound of the metal A (wherein A is at least one metal selected from the group consisting of Sr, Ca, Mg, Y, Ce, Yb, Zn and Ba), to obtain a mixture which contains such amounts of the ingredients [a], [b]
and [c] that the mixture produces a synthesized product La1-xAxMnO3 (wherein x is more than 0 but is not more than 0.5 when fired:
(ii) prefiring the mixture at a temperature of 1,400 to 1,700 °C to obtain the synthesized product La1-xAxMnO3; and (iii) preparing an air electrode material substantially consisting of La1-xAxMnO3, wherein the air electrode material preparation step comprises:
[A] (iv) pulverizing the synthesized product La1-xAxMnO3 to a powder having an average grain size of 1 to 10 µm, (v) mixing the powder with water and an organic binder, (vi) forming the resulting mixture into a shape desired for an air electrode, and (vii) subjecting the shaped mixture to a final firing at a temperature of 1,300 to 1,800°C to prepare the air electrode of a self-supporting type, or [B] (viii) pulverizing the synthesized product La1-xAxMnO3 to a powder, (ix) mixing the powder with water, an organic binder and a pore-increasing agent to prepare a slurry, (x) coating a surface of a porous support zirconia or a solid electrolyte zirconia with the slurry and (xi) subjecting the coating to a final firing at a temperature of 1,300 to 1,800°C to prepare the air electrode of a coating type.
(i) mixing [a] lanthanum or a lanthanum compound, [b]
manganese or a manganese compound and [c] a metal A or a compound of the metal A (wherein A is at least one metal selected from the group consisting of Sr, Ca, Mg, Y, Ce, Yb, Zn and Ba), to obtain a mixture which contains such amounts of the ingredients [a], [b]
and [c] that the mixture produces a synthesized product La1-xAxMnO3 (wherein x is more than 0 but is not more than 0.5 when fired:
(ii) prefiring the mixture at a temperature of 1,400 to 1,700 °C to obtain the synthesized product La1-xAxMnO3; and (iii) preparing an air electrode material substantially consisting of La1-xAxMnO3, wherein the air electrode material preparation step comprises:
[A] (iv) pulverizing the synthesized product La1-xAxMnO3 to a powder having an average grain size of 1 to 10 µm, (v) mixing the powder with water and an organic binder, (vi) forming the resulting mixture into a shape desired for an air electrode, and (vii) subjecting the shaped mixture to a final firing at a temperature of 1,300 to 1,800°C to prepare the air electrode of a self-supporting type, or [B] (viii) pulverizing the synthesized product La1-xAxMnO3 to a powder, (ix) mixing the powder with water, an organic binder and a pore-increasing agent to prepare a slurry, (x) coating a surface of a porous support zirconia or a solid electrolyte zirconia with the slurry and (xi) subjecting the coating to a final firing at a temperature of 1,300 to 1,800°C to prepare the air electrode of a coating type.
2. The process according to claim 1, wherein the alternative [A] is chosen in the air electrode material preparation step, whereby the air electrode of a self-supporting type is produced.
3. The process according to claim 2, which further comprises providing a coating of a solid electrolyte zirconia on a surface of the air electrode.
4. The process according to claim 3, wherein the coating of the solid electrolyte zirconia is formed by plasma spray; and thereafter the resulting air electrode-solid electrolyte composite is heat treated at about 1300°C.
5. The process according to claim 3, wherein the coating of the solid electrolyte zirconia is formed by applying a slurry of Y203-stabilized zirconia and the thus-coated air electrode is fired at about 1,300°C.
6. The process according to claim 2, wherein the temperature of the final firing is chosen so that the air electrode has a porosity of 25 to 35%.
7. The process according to any one of claims 1 to 6, wherein the metal A is Sr.
8. The process according to claim 7, wherein x is about 0.2.
9. The process according to claim 7, wherein La203, Mn304 and Sr Co3 are used as the ingredients [a], [b] and [c], respectively, in step (i).
10. A method of producing an air electrode material for solid electrolyte type fuel cells, comprising a process of mixing lanthanum or a lanthanum compound, manganese or a manganese compound, and a metal ? or a compound of the metal A wherein A is at least one metal selected from the group consisting of Sr, Ca, Mg, Y, Ce, Yb, Zn and Ba, a process of firing the resultant mixture at a temperature of at least 1,400°C to obtain a synthesized product La1-xAxMnO3 wherein x is 0<x?0.5 and A is as described above, and a process of treating the synthesized product La1-xAxMnO3 to produce an air electrode material substantially consisting of La1-xAxMnO3.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2-182,808 | 1990-07-12 | ||
| JP2182808A JPH0697613B2 (en) | 1990-07-12 | 1990-07-12 | Method for producing air electrode material for solid oxide fuel cell |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2046567A1 CA2046567A1 (en) | 1992-01-13 |
| CA2046567C true CA2046567C (en) | 1995-10-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002046567A Expired - Fee Related CA2046567C (en) | 1990-07-12 | 1991-07-09 | Method of producing an air electrode material for solid electrolyte type fuel cells |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5266419A (en) |
| EP (1) | EP0467590B1 (en) |
| JP (1) | JPH0697613B2 (en) |
| CA (1) | CA2046567C (en) |
| DE (1) | DE69105652T2 (en) |
Families Citing this family (20)
| Publication number | Priority date | Publication date | Assignee | Title |
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| DE4104838A1 (en) * | 1991-02-16 | 1992-08-20 | Abb Patent Gmbh | CERAMIC MATERIAL FOR PRODUCING A REINFORCING LAYER FOR THE AIR ELECTRODE OF A FUEL CELL WITH SOLID ELECTROLYTE |
| JPH05190180A (en) * | 1992-01-13 | 1993-07-30 | Ngk Insulators Ltd | Air electrode body of solid electrolyte type fuel cell, manufacture of air electrode body and solid electrolyte type fuel cell |
| CA2099443A1 (en) * | 1992-07-01 | 1994-01-02 | Prabhakar Singh | Fuel cell containing stable air electrode material |
| US5432024A (en) * | 1992-10-14 | 1995-07-11 | Ngk Insulators, Ltd. | Porous lanthanum manganite sintered bodies and solid oxide fuel cells |
| DE69411047T2 (en) * | 1993-02-05 | 1998-12-03 | Murata Mfg. Co., Ltd., Nagaokakyo, Kyoto | Semiconducting ceramic materials with negative temperature coefficient of resistance |
| DE4406276B4 (en) * | 1993-02-26 | 2007-10-11 | Kyocera Corp. | Electrically conductive ceramic material |
| US5604048A (en) * | 1993-02-26 | 1997-02-18 | Kyocera Corporation | Electrically conducting ceramic and fuel cell using the same |
| JP2846567B2 (en) * | 1993-09-03 | 1999-01-13 | 日本碍子株式会社 | Porous sintered body and solid oxide fuel cell |
| EP0669296B1 (en) * | 1994-02-23 | 1998-03-04 | Samsung Electronics Co., Ltd. | Method for forming a composite metal oxide and method for manufacturing an electrode using the same |
| US6096449A (en) | 1997-11-20 | 2000-08-01 | Avista Labs | Fuel cell and method for controlling same |
| US6030718A (en) | 1997-11-20 | 2000-02-29 | Avista Corporation | Proton exchange membrane fuel cell power system |
| USRE39556E1 (en) * | 1997-11-20 | 2007-04-10 | Relion, Inc. | Fuel cell and method for controlling same |
| MXPA01010639A (en) | 1999-04-20 | 2003-08-20 | Zinc Air Power Corp | Lanthanum nickel compound/metal mixture as a third electrode in a metal-air battery. |
| US7326480B2 (en) | 2000-05-17 | 2008-02-05 | Relion, Inc. | Fuel cell power system and method of controlling a fuel cell power system |
| US6468682B1 (en) | 2000-05-17 | 2002-10-22 | Avista Laboratories, Inc. | Ion exchange membrane fuel cell |
| US20040018409A1 (en) * | 2002-02-28 | 2004-01-29 | Shiqiang Hui | Solid oxide fuel cell components and method of manufacture thereof |
| US7691284B2 (en) * | 2006-08-29 | 2010-04-06 | The Boeing Company | Tunable variable emissivity materials and methods for controlling the temperature of spacecraft using tunable variable emissivity materials |
| US9120245B1 (en) | 2007-05-09 | 2015-09-01 | The United States Of America As Represented By The Secretary Of The Air Force | Methods for fabrication of parts from bulk low-cost interface-defined nanolaminated materials |
| US9162931B1 (en) * | 2007-05-09 | 2015-10-20 | The United States Of America As Represented By The Secretary Of The Air Force | Tailored interfaces between two dissimilar nano-materials and method of manufacture |
| US8617456B1 (en) | 2010-03-22 | 2013-12-31 | The United States Of America As Represented By The Secretary Of The Air Force | Bulk low-cost interface-defined laminated materials and their method of fabrication |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| GB1302819A (en) * | 1970-07-17 | 1973-01-10 | ||
| JPS51150692A (en) * | 1975-06-20 | 1976-12-24 | Arita Kosei | High conductivity composed substance |
| DE2614728A1 (en) * | 1976-04-06 | 1977-10-20 | Bbc Brown Boveri & Cie | COMPONENT FOR AN ELECTROCHEMICAL BATTERY |
| DE2738756A1 (en) * | 1977-08-27 | 1979-03-01 | Bbc Brown Boveri & Cie | Electrochemical cell for determining oxygen in exhaust gas - using reference electrode coated with metal oxide catalyst layer |
| US4562124A (en) * | 1985-01-22 | 1985-12-31 | Westinghouse Electric Corp. | Air electrode material for high temperature electrochemical cells |
| US4596750A (en) * | 1985-03-15 | 1986-06-24 | Westinghouse Electric Corp. | Support tube for high temperature solid electrolyte electrochemical cell |
| CA1302486C (en) * | 1987-04-06 | 1992-06-02 | Philip Reichner | Low circumferential voltage gradient self supporting electrode for solidoxide fuel cells |
| US4751152A (en) * | 1987-04-06 | 1988-06-14 | Westinghouse Electric Corp. | High bulk self-supporting electrode with integral gas feed conduit for solid oxide fuel cells |
| JP2622261B2 (en) * | 1987-10-05 | 1997-06-18 | 三菱重工業株式会社 | Method for manufacturing solid electrolyte fuel cell |
| JPH0669907B2 (en) * | 1989-04-28 | 1994-09-07 | 日本碍子株式会社 | Method for manufacturing electron conductive porous ceramic tube |
-
1990
- 1990-07-12 JP JP2182808A patent/JPH0697613B2/en not_active Expired - Lifetime
-
1991
- 1991-07-08 US US07/726,782 patent/US5266419A/en not_active Expired - Lifetime
- 1991-07-09 CA CA002046567A patent/CA2046567C/en not_active Expired - Fee Related
- 1991-07-11 EP EP91306285A patent/EP0467590B1/en not_active Expired - Lifetime
- 1991-07-11 DE DE69105652T patent/DE69105652T2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP0467590A1 (en) | 1992-01-22 |
| DE69105652D1 (en) | 1995-01-19 |
| DE69105652T2 (en) | 1995-06-14 |
| JPH0697613B2 (en) | 1994-11-30 |
| EP0467590B1 (en) | 1994-12-07 |
| CA2046567A1 (en) | 1992-01-13 |
| US5266419A (en) | 1993-11-30 |
| JPH0471166A (en) | 1992-03-05 |
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